diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-04-01 09:34:40 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-19 15:32:04 +0200 |
| commit | 2967178d30ee1109979239ff4f2f99f04d77a911 (patch) | |
| tree | 61a4477e4a651cca628ade0b3080b23700cec082 | |
| parent | 1be2000b703b02e149f8f2061054489f6c18c972 (diff) | |
x86/irq: Ensure initial PIR loads are performed exactly once
[ Upstream commit 600e9606046ac3b9b7a3f0500d08a179df84c45e ]
Ensure the PIR is read exactly once at the start of handle_pending_pir(),
to guarantee that checking for an outstanding posted interrupt in a given
chuck doesn't reload the chunk from the "real" PIR. Functionally, a reload
is benign, but it would defeat the purpose of pre-loading into a copy.
Fixes: 1b03d82ba15e ("x86/irq: Install posted MSI notification handler")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20250401163447.846608-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/x86/kernel/irq.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index feca4f20b06a..85fa2db38dc4 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -414,7 +414,7 @@ static __always_inline bool handle_pending_pir(u64 *pir, struct pt_regs *regs) bool handled = false; for (i = 0; i < 4; i++) - pir_copy[i] = pir[i]; + pir_copy[i] = READ_ONCE(pir[i]); for (i = 0; i < 4; i++) { if (!pir_copy[i]) |